Fluid pressure brake



April 20, 1937. E. E. HEwlTT FLUID PRESSURE BRAKE Filed Sept. l2, 1936 le 24 E8 3o s@ 35 s? 2a 2Q n l/llllllll C1 8 60:61am

INVENTOR E L LIS EHEWITT ATTORN EY Patented pr'. 20, 1937 PATENT GFFICE FLUID PRESSURE BRAKE Ellis E. Hewitt, Edgewood, Pa., assigner to The Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Application September 12, 1936, Serial No.'100,490

4 Claims.

'Ihis invention relates to fluid pressure brakes, and more particularly to a locomotive fluid pressure brake equipment.

The well known distributing valve provided in the ET locomotive brake equipment comprises an equalizing portion and an application portion, which includes valve means adapted to be operated by the pressure of fluid in an application cylinder to effect the supply of fluid under presl sure to the locomotive brake cylinders, and upon a reduction in fluid pressure in the application cylinder to release fluid under pressure from the brake cylinders. If the frictional resistance to movement of the valve means in the distributing valve application portion should become too great, due to accumulation of dirt in the application piston cylinder or other cause, the proper operation of the Valves means to vent fluid under pressure from the locomotive brake cylinders in effeoting a release of the brakes might be undesirably delayed or even prevented.

The principal object of my invention is to provide means adapted to be associated with a distributing valve device inthe above type of fluid pressure brake equipment for ensuring the prompt release of the brakes.

In the accompanying drawing, the single figure is a diagrammatic, sectional View of a uid pressure brake equipment embodying my invention.

As shown in the drawing, the equipment may comprise a distributing valve device I, a brake cylinder 2, a main reservoir 3, and a release valve device 4. Y

'I'he distributing valve device I comprises an equalizing portion which includes a slide valve mounted in a valve chamber I and adapted to be operated in the usual manner by a piston (not shown) according to variations in the pressure of fluid in a brake pipe 6, and an application portion, which comprises a piston 8 subject to the pressure of fluid in an application cylinder 9, an exhaust slide valve I8 contained in a valve chamber I I, and an application slide Valve I2 contained in a chamber I3, said slide valves I9 and 45 I2 being adapted to be operated by the piston 8.

The valve chamber I3 communicates by way of a passage and pipe I4 with the main reservoir 3.

According to the invention, the release valve device 4 comprises casing sections I6 and I'I sc- 50 cured together by any suitable means, such as bolts (not shown). Formed in the casing section I6 is a chamber I 8 connected through a passage and pipe I9 and a pipe 28 with the brake cylinder 2, and communicating by way of an 55 aperture 22'formed in a web 23 with a chamber 24, which is open to atmosphere through a restricted passage in a choke plug 26. For controlling communication between the chambers I8 and 24 there is provided a flexible diaphragm 28 which has an annular seat rib 29 aligned for seat- 5 ing engagement with a seating face 30 surrounding the aperture 22 of the Web 23. The diaphragm 28 is mounted between the web 23 and a plate 32 secured to the web by any suitable means such as screws 33, and has a central stud 10 35 formed on the lower side thereof on which is fitted an annular member 36 which is subject to the force of a coil spring 31 arranged to bias the rib 29 of the diaphragm away from the seating face 39. 15

Engaging the upper side of the diaphragm 28 is a follower member 40, the upper end of which extends through a central opening in the plate 32 and is engaged by a follower plate 4I that is in engagement with the under side of a flexible 20 diaphragm 42 mounted between the casing sections IS and Il.A The diaphragm 42 has a larger pressure area than the diaphragm 28, and together with the casing section I'I defines va chamber 43 connected through a restricted passage 44 25 in a choke plug with a chamber 45 in said casing section, which communicates by way of a pipe 48 with the application cylinder 9 in the distributing valve device I.

Upward movement of the diaphragm 42 is lim- 30 ited by a stop portion 48 formed on the casing section I'I. A chamber 49 is formed between the diaphragms 42 and 28 and is always open to the atmosphere by way of a restricted passage 50 in a choke plug and a passage 5I provided in the 35 casing section I6.

The operation of the distributing valve device I is well known in the art and need not be described in detail. With the parts of the distributing valve device in the release position as 40 shown in the drawing and assuming that the well known automatic and independent brake valves are in running position, the application cylinder 9 and the chamber 43 of the release valve device connected thereto are vented by way 45 of passages 52 and 53, a cavity 54 in the equalizing slide valve 5, a passage 55 and the usual release pipe 56, which is connected through said brake valve devices in running position With the atmosphere. At the same time, the brake eylin- 5o der 2 is connected with the atmosphere by way of the pipe 20, passage 5l in the distributing valve device I, the chamber II and exhaust port 58, and also by way of the pipe I9, chamber I8 of the release valve device 4, aperture 22, cham- 55 a valve operative to control the release of uid under pressure from the brake cylinder, a spring, and movable abutment means subject on one side to the pressure of fluid in said application chamber and on the opposite side to the pressure of said spring and brake cylinder pressure for operating said valve.

3. In a fluid pressure brake, in combination, a brake cylinder, a distributing valve device comprising valve means operable according to variations in fluid pressure in an application chamber for controlling the supply and release of uid under pressure to and from the brake cylinder, and an auxiliary release valve device comprising a Valve operative to eiect the release of fluid from the brake cylinder, and a pair of movable abutments for controlling the operation of said valve, one of said abutments having a larger area than the other and being subject to the pressure of fluid in the application chamber and the other abutment being subject to the pressure of fluid in the brake cylinder.

4. In a fluid pressure brake, in combination, a brake cylinder, a distributing valve device comprising valve means operable according to variations in fluid pressure in an application chamber for controlling the supply and release of iluid under pressure to and from the brake cylinder, and an auxiliary release valve device comprising valve means for controlling the release of fluid from the brake cylinder and movable abutment means subject on one side to the pressure in a chamber which is connected to the application chamber through a restricted port and on the opposite side to brake cylinder pressure.

ELLIS E. HEWI'IT. 

